In many conventional air-conditioning systems, the system includes an outdoor air conditioning unit (OACU) and one or more indoor air conditioning units (IACUs) in one or more rooms of a structure, respectively. The outdoor air conditioning unit provides supply air at a base temperature, while the individual IACUs refine the temperature of the air in the individual rooms to achieve a desired air temperature.
In addition to heating and cooling air, many air conditioning systems also operate to remove humidity from the air they provide. This is generally done by cooling the outdoor air down to the dew point (55° F.) in the OACU, at which point moisture will condense out of the air.
Since 55° F. is typically colder than the temperature most users desire for their air, air conditioning systems that remove humidity from the air also typically have a heater such that the dehumidified air can be reheated at the OACU before it is provided to the individual rooms in the structure at the base temperature. Typically, the base temperature of supply air is approximately the desired temperature for the room or rooms. In other words, in an ideal circumstance, the OACU would perform all of the work, providing air at the desired temperature.
However, the individual rooms can often have an air conditioning load associated with them. This air conditioning load represents an amount of heating or cooling that must be performed on the supply air to bring the air in the room to the desired temperature (i.e., the temperature set by an occupant of the room). For example, if a room is full of people, that will tend to raise the temperature in that room. If the base temperature of the supply air is approximately the desired temperature, then the people in the room will raise the room's temperature, requiring an associated IACU to cool the air. Likewise, if the temperature outside the room, or outside the structure, is significantly different than the desired temperature in the room, this may cause the temperature in the room to move away from the base temperature of the supply air, again requiring an IACU to heat or cool the air so that it can reach the desired temperature.
In situations in which the air is dehumidified and the air conditioning load in a room requires an IACU to cool the air, this may result in the OACU heating the air, while one or more IACUs cool the air. This is a waste of energy, since the OACU and the IACU are working at cross purposes.
It would therefore be desirable to have an air conditioning system in which the heating of air by an OACU was regulated so as to minimize the total power expended by the OACU and any associated IACUs.